Frequency responsive lubrication system



FREQUENCY RESPONSIVE LUBRICATION SYSTEM 2 Sheets-Sheet 1 Filed July 10,1967 FIG.I

INVENTORSI GEORGE VD. BROOKS,

DALE A. FARRINGTON,

JOHN E. FOLEY, BY 1% C- THEIR ATTORNEY.

July 9, 1968 BROOKS 3,391,602

FREQUENCY RESPONSIVE LUBRICATION SYSTEM Filed July 10, 1967 2Sheets-Sheet 2,

u so i 7 II 2, 7 66 a2 46 j J. 5 84 as 89 FIG.4

3 GUN DISPLACEMENT 5 AT 70 e IOOCPS Z T Z IJJ 2 3 f, PUMP (PISTON ROD)DISPLACEMENT O. m 5 .06

TIME

INVENTORS'. GEORGE D. BROOKS, DALE A. FARRINGTON, JOHN E. FOLEY,

THEIR ATTORNEY.

United States Patent O 3,391,602 FREQUENCY RESPONSIVE LUBRICATION SYSTEMGeorge Dewey Brooks, South Burlington, and Dale Andrew Farrington,Winooski, Vt., and John Emmet Foley, Longmeadow, Mass., assignors toGeneral Electric Company, a corporation of New York Filed July 10, 1967,Ser. No. 652,308 4 Claims. (Cl. 89-1) ABSTRACT OF THE DISCLOSURE Incombination, a very high rate of fire automatic weapon operating on theGatling-gun principle and a frequency responsive device for deliveringlubricant to the internal gun mechanism. The device comprises alubricant reservoir, pick-up and delivery lines, and a piston operableagainst a spring force, in a pump chamber connecting the lines, by aweight or mass attached to the piston rod. The reservoir is mounted onthe gum and the weight-rod-piston selected to act as a vibratingmassspring system at gun operating frequencies.

Background of the invention It is well known to use lubricating devicesfor guns wherein cams or levers are operated by gun recoil to pumplubricant to the internal gun mechanism. In such manner a gun bolt whichrides on a track in the receiver may be continuously supplied with oilor grease. Such devices are usually somewhat undesirable under adversefield conditions, however, since reliability sufiers the more complexthe apparatus. It is also known to use mass or weight which, whensuddenly accelerated, can be used to do work through the effects ofinertia. That is, if attached to a lever which remains stationary, forexample, the inertia of the suddenly accelerated mass will apply a forceto the lever which can be made to do useful work. Such a device would bemore reliable in concept than the typical recoil-operated cam and leverarrangement. Means are needed, however, to adapt this for use with amodern, high rate of fire weapon operating on the Gatling-gun principle.Such a weapon is described in detail in the patent to Otto 2,849,921.Due to its extremely high rate of fire the modern day Gatling-gun, asshown in Ottos patent, establishes what may be termed an operatingfrequency of vibration as the six (or more) gun bolts reciprocate in therotor tracks which are revolving about the gun axis. We have takenadvantage of this phenomenon to provide an improved and simplified meansof internally lubricating such a weapon.

Accordingly, a general object of our invention is to provide an improvedlubricating device for a high rate of fire automatic weapon.

A more specific object of our invention is to provide, in combination, ahigh rate of fire automatic weapon of the Gatling-gun type and alubricating device actuated in response to the rapid vibrating motion ofthe internal gun mechanism.

Summary of the invention In the disclosed embodiment the inventioncomprises a lubricator having a housing or reservoir casing adapted tocontain lubricant, an inner support member, pick-up and delivery linesfor oil contained within the housing, a pump chamber in flowrelationship with the lines, a piston within the chamber having anelongated actuator rod, and a mass or weight retained on the rod at theopposite end of the piston externally of the reservoir. The lubricatoris utilized with a high rate of fire automatic weapon operating on theGatling-gun principle and having a plu- 3,391,602 Patented July 9, 1968"ice Other objects and advantages of our invention will become moreevident from the claims appended hereto, when read in the light of thefollowing detailed description with the accompanying drawings in which:

FIG. 1 is an external view of a rapid-fire weapon of the Gatling-guntype with lubricator mounted thereon, illustrating the overall gun andthe external lubricator configuration and delivery line location;

FIG. 2 is an end view of the gun and lubricator assembly of FIG. 1,illustrating the lubricant feed line to the FIG. 3 is a cross-sectionalview of a preferred embodiment of the lubricator; and

FIG. 4 is a graph illustrating the output flow of lubricant during atypical gun burst period.

Description of the preferred embodiment As seen in FIGS. 1 and 2 theautomatic weapon comprises a plurality of barrels 10 mounted on a rotorbody 12 rotatably supported in a gun housing indicated generally at 14.The gun is adapted to be supported by means (not shown) carried on avehicle which may be an aircraft, tank, personnel carrier, or the like,depending on the tactical mission for which the weapon is designed. Inany event, the rotor 15 revolves about the gun axis when driven bysuitable external or internal power means (not shown). As seen in FIG.2, the gun has a plurality of bolts, one of which is partially shown at16. The bolts ride in tracks or ways 18 machined in the rotor bodyperiphery. As stated above, a more complete description of the gunmechanism may be found in the patent to Otto 2,849,921. It will sufiicefor describing our invention to say that the bolts reciprocate rapidlyin the cam tracks as the gun is operated at firing rates up to andexceeding 6000 shots per minute (s.p.m.), depending on the size of theweapon. This very high rate of fire which is unique to the modern dayGatling-gun results in a substantially steady vibration of the overallgun. The vibration typically has a specified amplitude and drivingfrequency rate depending on the rate of fire of the gun. The systemsdriving frequency can be ascertained therefor for any given gun andassociated equipment. We have taken advantage of this phenomenon tocombine with the gun a frequency responsive system in the form of alubricator pump mechanism. That is, the lubricator, which is indicatedgenerally at 30 in the drawings, fimctions, in part, as a vibrationactuated mass-spring system.

Turning to FIG. 3 for a description of the lubricator in detail, it willbe seen to include an outer casing or housing 32 which forms a reservoirfor the lubricant (oil or grease), indicated generally at 34. The outercasing is sealed, at 36, to a mounting flange 38 adapted to be suitablyfastened at 39 to a gun housing flange, indicated at 1411. Supportedwithin the reservoir by suitable means, such as bolts ill-40, is aninternal support assembly or frame indicated generally at 42. The frame42, in turn, supports an intake lube line 44 having a downwardly openingpick-up orifice 44a, an internal delivery line 46 connected to an exitfitting 48 fastened in an opening 49 in flange 38, and a pump assemblyindicated generally at 50. The pump assembly is a hollow body having anupright (in the diawing) intake portion 52, a piston chamber portion 54extending perpendicular to the intake portion 52 and in flowcommunication therewith, and an exit or delivery portion 56. The pumpintake section 52 is connected through fitting 52a to intake line 44,while the pump exit section 56 is connected through a fitting 56a to theinternal delivery line 46. Fittings 52a and 56a are threaded orotherwise securely fastened intermediate lines 44 and 46, respectively,and the pump assembly and effectively support the pump assembly on frame42 by projecting through holes in the supporting frame, as is indicatedat 58 and 60 on the frame. Obviously, other means of supporting thelines and the pump assembly will occur to those skilled in the art, andthe configuration shown is for purpose of illustration only.

The pump assembly 50 will now be described in more detail. As seen inFIG. 3, the intake passage 60 contains a one-way flow restrictor, inthis case a typical ball-check valve arrangement indicated generally at62. Lubricant flow passes through orifice 62a, therefore, in onedirection only, i.e., downward (in the drawing) and into the pistonchamber interior 54a. A hollow piston sleeve 64 connected to one end at65 to a piston or actuator rod 66 is operable against a spring 68contained by the sleeve 64 and bottoming on the pump chamber far wall,at 69. The rod 66 projects through an opening in the end of wall of thechamher, at 70, the pump wall being held in location against the frame42 by suitable means such as a threaded bushing 72. At the opposite endof the housing 32 from flange 38 is an enlarged pad 74 projectinginwardly of the reservoir. Pad 74 has a central opening 76 into which isfitted cylindrical bearing means 78. The bearing means supports rod 66which extends through the pad opening and a smaller aligned opening at80 in the casing wall. A suitable sealing member 82 closes opening 76 tolubricant How. The other end of the actuator rod 66 projectssubstantially beyond the reservoir, being received in a cover portion 84of the lubricator housing. The cover encloses a mass or actuator weight86 securely fastened by suitable means, such as nut 89 to the end of therod. The exit or delivery portion 56 also includes a one-way ball checktype valve assembly, indicated generally at 90, for purposes now to bedescribed.

In operation, it will be assumed that the gun shown has C a normalmaximum firing rate of approximately 6000 s.p.m. A typical drivingfrequency for a gun of a given weight was therefore found to be about100 c.p.s. at an acceleration rate on the order of 70 Gs. The lubricator30 was therefore designed to take advantage of this phenomenon, asstated above, by providing that the pump assembly piston, piston rod,and weight 86, together with spring 68, function as a vibratingmass-spring system. This is in contrast to the conventional inertiasystem which would utilize a full displacement of the piston which wouldoccur at the beginning of weapon operation and at shut-off, in a weaponof the type shown in the aforementioned Otto patent. Thus, we haveprovided a gun lubricating system wherein a continuous and sustainedsupply of lubricant is provided as the gun operates.

To explain in more detail, as the weapon vibrates the piston moves backand forth in the chamber 54a in response to the effect of the vibrationon the weight or mass 86. On the intake stroke (movement to the left inthe drawing) valve 62 opens and the chamber 54a fills. On the delivery(opposite movement) stroke, valve 62 closes and valve 90 opens todeliver lubricant. It was also discovered that the pump assembly pistonaction can operate as a damper on the vibrating mass-spring mechanismdescribed above due to the fact chamber 54a is filled with lubricantwhich is being moved. Orifices 62a and 90a can be adjusted to regulatethis as can the mass-weight 86-be also conveniently adjusted to give amaximum level of continuous and regular displacement of the pump pistonat a particular driving frequency using the relationship:

where,

X =maximum piston rod displacement F=force, tag, 70 G acceleration levelacting on the mass K=the spring gradient (e.g., spring 68) u=amagnification factor which is a function of the ratio of the vibration(driving) frequency (V to the natural frequency of the mass-springsystem (W and the damping ratio (P), or

In one case, the maximum piston displacement for a weight of 0.6 poundwas found to be .06 inch, where the gun vibration or driving frequencywas c.p.s. at the 70 G acceleration level or 0.25 inch, as seen in thegraph of FIG. 4. The magnification factor (a), on the other hand, islimited in effect for damping ratios on the order of 1 or greater. Inthe apparatus of our invention damping ratios are selected to be 1 orgreater and, further, the damping ratio will increase with increasedviscous damping, i.e., lower lubricant temperatures. Thus, for a typicalfiring burst, such as is shown pictorally in FIG. 4, lubricant isdelivered to the gun bolt tracks on a sustained basis, rather thanperiodically at starting and stopping of the weapon operation.

While other machines having the vibratory motion pecular to theapparatus shown herein could also utilize our lubricating system, it hasbeen found to be quite effective for weapons of the Gatling-gun variety.Such weapons can have a vibratory range of approximately 20-200 c.p.s.,in which case the piston mass or weight could vary from .0 to 2.0pounds. In such cases, the spring gradient, of the mass-spring system,could range from 1 pound/ inch to 50 pounds/ inches.

The frequency responsive gun lubricating system of our invention, asdescribed above, has been shown to have substantial advantages inoperating reliability over the more complex cam and lever operatedinertia systems. It will be understood, however, that the claimsappended hereto are intended to cover obvious modifications and changesin the lubricator design and in the mass-spring pump mechanism hereinillustrated as will occur to those skilled in the art.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. Frequency responsive lubricator apparatus for a high rate of fireautomatic weapon having a plurality of barrels radially grouped forrotation about a common axis and a plurality of bolt assemblieslongitudinally movable parallel to said axis and rotatable with saidbarrel group, said Weapon having a vibration-generated operatingfrequency, said lubricator apparatus comprising:

a lubricant reservoir adapted to be aflixed to the automatic weapon;

conduits in flow communication with said reservoir for pick-up anddelivery, respectively, of lubricant to said weapon;

and pump means interconnecting said pick-up and delivery conduits, saidpump means including a massspring mechanism operable in response to thevibration-generated operating frequency to cause said pump means toprovide a continuous, regular amount of lubricant to said weapon duringits operating period.

2. The apparatus of the invention according to claim 1 wherein said pumpmeans includes an intake section connected to the pick-up conduit, afirst check valve inv said intake section, a delivery section connectedto the delivery conduit, 21 second check valve in said delivery section,and a piston chamber intermediate said intake and said deliverysections, and wherein said mass-spring mechanism includes a hollowpiston member reciprocally movable in said chamber, a spring partiallyenclosed by said piston and bottoming on a chamber well, an elongatedactuator rod attached at one end to the piston and projecting axiallytherefrom externally of said reservoir, and a mass of predeterminedweight affixed to the other end of said actuator rod.

3. In combination: an automatic weapon, said weapon having a rotor, ahousing supporting said rotor for rotation about its longitudinal axis,a plurality of barrels mounted on said rotor in a radial grouping aboutsaid axis, a plurality of bolt assemblies reciprocally movable in axialtracks on the periphery of said rotor, and means to power said rotorduring weapon operation to discharge cartridges alternately andsequentially through said barrels, said weapon operation generating avibratory frequency dependent on the speed of rotation of said rotor;and lubricator apparatus afiixed to said weapon housing,

said apparatus comprising,

a lubricant reservoir,

an intake conduit within said reservoir having a pick-up openingimmersed in the lubricant,

a delivery conduit, said delivery conduit operatively connecting saidreservoir to the rotor tracks,

pump means interconnecting said conduits within said reservoir, saidpump means including a lubricant chamber, a first check valve on theintake side of the chamber, and a second check valve on the deliveryside of the chamber, and

a mechanism operable to cause sequential opening and closing of saidfirst valve for charging said chamber with lubricant and sequentialclosing and opening of said second valve for discharging said chamber,said mechanisrn comprising a hollow piston slidingly received in saidchamber, an axially-extending actuator rod attached at one end to saidpiston, said rod projecting outwardly of said reservoir through an endwall of said chamber, a spring partially enclosed by said piston andbottoming on a wall of said chamber opposite said end Wall, and 'aweight affixed to the other end of said actuator rod,

said piston, said rod and said weight together with said springcomprising a mass-spring system responsive to the operating vibratoryfrequency of said weapon to cause lubricant to be pumped thereto.

4. The invention of the apparatus according to claim 3 wherein theweight of said mass-spring system has an approximate range of 0.1 to 2.0pounds and said spring has an approximate gradient range of 1.0 pound/inch to 50 pounds/inches.

References Cited UNITED STATES PATENTS 1,351,017 8/1920 Blackmore 891.22,849,921 9/1958 Otto 8912 SAMUEL W. ENGLE, Primary Examiner.

